This text is based on a press release by Monash University
A global analysis of range-shift records for 1,758 butterfly species – 10 per cent of known butterfly species – found that 80 per cent had expanded their range and that 79 per cent of all recorded range shifts were linked to climate change and extreme weather events. The new study, published in Nature Ecology & Evolution, also reports range contractions for 27 per cent of species, and 22 per cent of species showed a change in elevation. Because many species exhibited multiple types of range shift, the percentages for expansions, contractions, and elevation changes is above 100%.
The study is the largest of its kind, analysing 6,182 range‑shift records across 105 countries and drawing on English and non‑English scientific literature as well as 68 expert assessments. It was led by researchers from Monash University, the German Centre for Integrative Biodiversity Research (iDiv), the Friedrich Schiller University Jena, and the Helmholtz Centre for Environmental Research (UFZ).
The analysis also reveals distinct global patterns in how butterfly ranges are shifting. Horizontal expansions were recorded on every continent, with particularly high numbers in tropical countries. Range contractions were seen more often in temperate regions, such as Europe and North America. Elevational shifts were almost exclusively in the Northern Hemisphere.
"We found butterfly species shifting their ranges on every continent where they occur", says first author Dr Shawan Chowdhury, alumnus of iDiv, the University of Jena, and the UFZ, who works now at Monash University in Melbourne. "The scale is astonishing, and it's happening far beyond the well‑studied regions of Europe and North America."
Butterflies are early‑change indicators, Chowdhury adds, noting that "if their ranges are shifting this dramatically, it signals profound changes across ecosystems."
Insufficient monitoring leaves many gaps
The study also makes clear that countries differ greatly in how well butterfly range shifts are being documented.
For example, in some European countries, like the Czech Republic, Finland, Luxembourg, Spain, and Sweden, records exist for more than half of the countries' butterfly species. In most other countries, however, range shifts have been documented for fewer than ten per cent of species, reflecting limited monitoring and absence of data.
By including non‑English studies and expert knowledge, the authors could generate a uniquely comprehensive global dataset. "Recording contributions from butterfly experts from society and efforts of natural history societies [was] hugely important to understand global butterfly biodiversity patterns," says Dr Aletta Bonn, research group head at UFZ and iDiv, and a professor at the University of Jena.
Still, severe geographic data gaps persisted in Central Africa, Southeast Asia, New Guinea, and the Amazon Basin, all critically under‑represented despite being global biodiversity hotspots.
"The study helps balance the picture, but it also demonstrates an urgent need of consorted action to expand monitoring efforts globally", explains senior author Dr Guy Pe'er of iDiv and UFZ. The authors emphasise that without equitable, standardised, and multilingual biodiversity monitoring, conservation efforts risk being guided by an incomplete evidence base.
